Thermodynamic analysis of waste heat recovery from hybrid system of proton exchange membrane fuel cell and vapor compression refrigeration cycle by recuperative organic Rankine cycle

Journal of Thermal Analysis and Calorimetry - According to day-by-day consumption increase, energy high costs and nonrenewable energy destroying effects, clean technologies such as fuel cells lead...     

Numerical study of heat transfer enhancement from a heated circular cylinder by using nanofluid and transverse oscillation

Journal of Thermal Analysis and Calorimetry - Adding nanoparticles into the base fluid and oscillating the target surface are two passive and active techniques, respectively, for heat transfer...     

Magnetically recyclable nano copper/chitosan in O‐arylation of phenols with aryl halides

Interaction of chitosan (CS) with Fe₃O₄, followed by embedding Cu nanoparticles (NPs) on the magnetic surface through adsorption of Cu²⁺, and its reduction to Cu^o via NaBH₄, offers a reusable efficient catalyst (Fe₃O₄/CS‐Cu NPs) that is employed in cross‐coupling reactions of aryl halides with phenols, which affords the corresponding diaryl ethers, with good to excellent yields. The catalyst is completely recoverable from the reaction mixture by using an external magnet. It can be reused four times, without significant loss in its catalytic activity.     

A Surrogate Modelling Approach Based on Nonlinear Dimension Reduction for Uncertainty Quantification in Groundwater Flow Models

Transport in Porous Media - In this paper, we develop a surrogate modelling approach for capturing the output field (e.g. the pressure head) from groundwater flow models involving a stochastic...     

In Situ Synthesis of a Novel Quinone Imine Self‐Assembled Monolayer and Consideration of Its Reactivity with L‐Arginine

In situ functionalization of a 4‐aminothiophenol (4ATP) self‐assembled monolayer (SAM) on a Au electrode (4ATP/Au SAM) by the Michael addition reaction is considered. Under optimized conditions, the nucleophilic attack of the amino group of 4ATP/Au SAM to give an electrogenerated ortho‐quinone produced a novel electroactive SAM (ESAM). The ESAM could be oxidized to quinone‐imine SAM (QI SAM) for the covalent immobilization of L ‐arginine monolayers. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Fourier transform infrared (FTIR) spectroscopy are employed to characterize these systems.. The apparent heterogeneous rate constant (k_s^app) for ESAM/Au and the rate constant (k′) of the pseudo‐first order Michael addition reaction of L ‐arginine and ESAM/Au are calculated.     

A novel two-phase group decision making approach for construction project selection in a fuzzy environment

This paper considers a construction project problem under multiple criteria in a fuzzy environment and proposes a new two-phase group decision making (GDM) approach. This approach integrates a modified analytic network process (ANP) and an improved compromise ranking method, known as VIKOR. To take uncertainty and risk into account, a new decision making approach is presented with multiple fuzzy information by a group of experts, and a risk attitude for each expert is incorporated that can be expressed linguistically. First, a modified fuzzy ANP method is introduced to address the problem of dependence as well as feedback among conflicting criteria and to determine their relative importance. Then, a fuzzy VIKOR method is extended to rank potential projects on the basis of their overall performance. An illustrative example from the literature is provided for the construction project problem to demonstrate the effectiveness and feasibility of the proposed approach. The computational results show that the proposed two-phase GDM approach is suitable to cope with imprecision and subjectivity for the complicated decision making problem. Finally, the associated results of the proposed approach with risk attitudes and without risk attitudes are compared with the results reported by Cheng and Li [1], and the merits are highlighted.     

Electromagnetic interference shielding effectiveness of reinforced composite with graphene oxide-lead oxide hybrid nanosheets

ABSTRACT

The rapid development of telecommunication devices and related technologies improved the distribution of electromagnetic (EM) waves within the environment, which can adversely affect the performance of electronic systems and put the life of living species in serious danger; thus, practical alternatives are required to protect vulnerable sources from them. To address this demand, we developed reinforced composites with graphene oxide (GO)-lead oxide (GO-Pb₃O₄) hybrid 2D nanosheets at diverse filler loadings by employing the vacuum shock technique. Next, the developed fillers and composites were well characterized by the diverse analysis methods and their electromagnetic interference shielding effectiveness (EMI SE) was evaluated and compared with their X-ray shielding performance. The obtained results showed that the developed composites can perfectly attenuate X-ray waves and weaken the total power of applied EM waves (in X-band frequency (8.2–12.4 GHz)) more than 50%. In this regard, a 6 mm thick specimen containing 10?wt% GO-Pb₃O₄ attenuated emitted X-ray waves equal to 4.06, 4.83 and 3.91?mmAl at 40, 60 and 80?kVp energies, which shows about 124%, 124% and 121% increase, respectively, in the X-ray attenuation compared with neat epoxy resin. These results indicated that developed composites are perfect candidates to protect vulnerable sources from diverse EM sources, and despite the insulative nature of the GO-Pb₃O₄, these hybrid nanosheets can act as a potential barrier against EM waves.     

Capacitated location allocation problem with stochastic location and fuzzy demand: A hybrid algorithm

In this article, a capacitated location allocation problem is considered in which the demands and the locations of the customers are uncertain. The demands are assumed fuzzy, the locations follow a normal probability distribution, and the distances between the locations and the customers are taken Euclidean and squared Euclidean. The fuzzy expected cost programming, the fuzzy β-cost minimization model, and the credibility maximization model are three types of fuzzy programming that are developed to model the problem. Moreover, two closed-form Euclidean and squared Euclidean expressions are used to evaluate the expected distance between customers and facilities. In order to solve the problem at hand, a hybrid intelligent algorithm is applied in which the simplex algorithm, fuzzy simulation, and a modified genetic algorithm are integrated. Finally, in order to illustrate the efficiency of the proposed hybrid algorithm, some numerical examples are presented.     

Optimizing multi-item multi-period inventory control system with discounted cash flow and inflation: Two calibrated meta-heuristic algorithms

A mixed binary integer mathematical programming model is developed in this paper for ordering items in multi-item multi-period inventory control systems, in which unit and incremental quantity discounts as well as interest and inflation factors are considered. Although the demand rates are assumed deterministic, they may vary in different periods. The situation considered for the problem at hand is similar to a seasonal inventory control model in which orders and sales happen in a given season. To make the model more realistic, three types of constraints including storage space, budget, and order quantity are simultaneously considered. The goal is to find optimal order quantities of the products so that the net present value of total system cost over a finite planning horizon is minimized. Since the model is NP-hard, a genetic algorithm (GA) is presented to solve the proposed mathematical problem. Further, since no benchmarks can be found in the literature to assess the performance of the proposed algorithm, a branch and bound and a simulated annealing (SA) algorithm are employed to solve the problem as well. In addition, to make the algorithms more effective, the Taguchi method is utilized to tune different parameters of GA and SA algorithms. At the end, some numerical examples are generated to analyze and to statistically and graphically compare the performances of the proposed solving algorithms.     

Gold nanoparticles functionalised with stable, fast water exchanging Gd3+ chelates as high relaxivity contrast agents for MRI

Gold nanoparticles functionalized with Gd(3+) chelates displaying fast water exchange, superb pH stability and inertness towards transmetalation with Zn(2+) have been prepared and characterized as a new high relaxivity (29 mM(-1) s(-1), 30 MHz, 25 °C) contrast agent potentially safe for in vivo MRI applications. The Lipari-Szabo treatment for internal rotation was used to evaluate the effect of linker flexibility on the relaxivity of the gold nanoparticles. The effect of fast water exchange on the relaxivity of gold nanoparticles functionalized with Gd(3+) chelates is also addressed in this communication.